Nah, this is 2020 mate, we are all used to purchasing stuff online from all over the place. It's no big deal. And besides, no one would care about what Apple charged if it was possible to have alternate stores, or just to purchase from anywhere on the web (just like you can on macOS). Then you would have other big names open stores, and people could trust them too (or not, as is their whim). There would still be an Apple iOS store, but also an Amazon, google, MS, Epic, etc iOS stores. There would be competition, and thus developers could choose any or all of the stores that had the prices/terms that they liked. Or developers could skip them all and just sell direct from their own website. Individual end users could decided which of those they trusted (just like macOS users do). Some would stick to just the Apple store (just like some macOS users do). I have a strong hunch that this will be the end result of the Apple/Epic battle.
Epic cannot win its legal fight with Apple. They thought they could sway Apple with developer (and consumer) opinion and get Apple to acquiesce over the bad PR their lawsuit supposedly wrought.
But as I stated above, consumers largely don’t care about a 30% tax they will never see or feel. I don’t think that app prices would decrease because any developer worth his salt prices them at a level to maximise revenue, because software doesn’t incur any marginal costs.
Likewise, users don’t actually dislike closed ecosystems. If anything, I will argue that the iphone is as popular as it is partly due to the locked-down nature of the iOS App Store being a trusted marketplace for users to download apps from. And the App Store doesn’t exist to serve developers; it exists for us consumers.
If it were as simple as what you stated, Epic wouldn’t be suing Google as well (since Google does allow sideloading). If Epic cared about doing the right thing, they wouldn’t have flaunted App Store rules so blatantly and flagrantly, leading the judge to rule that this whole mess was entirely of Epic’s own making.
To sum it up, I don’t think current anti-trust arguments against Apple are holding up to scrutiny. Not by Epic, not by this new coalition I am happily dubbing the “suicide squad”. Epic is fighting an impossible battle, and they are going to lose, now that Apple has dug in their heels, counter-sued Epic, shows absolutely no signs of relenting, and is happy to drag it out for as long as needed considering the utter lack of backlash over the removal of Fortnite on its platform.
Developers can only hope that this whole saga doesn’t sour the goodwill that Apple still has for them. For when Epic loses the lawsuit (and they will), the consequences will be dire for the entire app ecosystem, because Apple will see this victory as evidence that they were right all along, and have even less motivation to want to make concessions to developers or accommodate them. Not when they have been declared to be the rightful law of the land.
Epic will lose, and developers can only hope there will still be a status quo for them to return to at the end of all this.